Despite the widespread use of marijuana, relatively little is known about the long term effects of the drug on neurocognitive and neurophysiologic function. The proposed investigation emerges from our studies of neuropsychological effects of marijuana in college students and adults, as well as from our previous investigations utilizing neuropsychological paradigms and functional magnetic resonance imaging (fMRI) to assess changes in regional cerebral activity in response to cognitive challenges. Neuropsychological assessments indicate that selected cortical functions, especially attentional and memory processing, are diminished after heavy cannabis use. Moreover, we have recently studied chronic marijuana smokers after a 28 day abstinence period, and found that performance on measures of memory and attention remained significantly reduced. The neural mechanisms underlying these cognitive deficits, the extent to which these functions may recover, and the time course of recovery remain to be clarified. To date, no study has incorporated focal neuroimaging using cognitive challenge paradigms and a lengthy period of monitored abstinence from the drug. Fast scan, fMRI techniques have increased the spatial and temporal for functional imaging beyond what has previously been available. We now propose to examine regional cerebral activation during cortical challenge paradigms in three study groups following 1 and 28 days of a monitored abstinence from marijuana. The three study groups will be comprised of 60 current heavy long-term smokers of marijuana, 60 former heavy long-term smokers of marijuana, and 60 light smokers of marijuana. This project will provide important new information regarding the type, presence, and magnitude of the effects of cannabis on brain function. Further, the identification of neural processes which demonstrate improvements in cognitive activation following abstinence may be critical for the development of intervention strategies, the design of new treatments, and decisions regarding public policy.
| Silveri, Marisa M; Jensen, John Eric; Rosso, Isabelle M et al. (2011) Preliminary evidence for white matter metabolite differences in marijuana-dependent young men using 2D J-resolved magnetic resonance spectroscopic imaging at 4 Tesla. Psychiatry Res 191:201-11 |
| Wollenweber, Frank Arne; Schomburg, Robert; Probst, Mareike et al. (2011) Width of the third ventricle assessed by transcranial sonography can monitor brain atrophy in a time- and cost-effective manner--results from a longitudinal study on 500 subjects. Psychiatry Res 191:212-6 |
| Silveri, Marisa M; Rogowska, Jadwiga; McCaffrey, Alexandra et al. (2011) Adolescents at risk for alcohol abuse demonstrate altered frontal lobe activation during Stroop performance. Alcohol Clin Exp Res 35:218-28 |
| Sneider, Jennifer T; Pope Jr, Harrison G; Silveri, Marisa M et al. (2008) Differences in regional blood volume during a 28-day period of abstinence in chronic cannabis smokers. Eur Neuropsychopharmacol 18:612-9 |
| Gruber, Staci A; Silveri, Marisa M; Yurgelun-Todd, Deborah A (2007) Neuropsychological consequences of opiate use. Neuropsychol Rev 17:299-315 |
| Yurgelun-Todd, Deborah (2007) Emotional and cognitive changes during adolescence. Curr Opin Neurobiol 17:251-7 |
| Pillay, Srinivasan S; Gruber, Staci A; Rogowska, Jadwiga et al. (2006) fMRI of fearful facial affect recognition in panic disorder: the cingulate gyrus-amygdala connection. J Affect Disord 94:173-81 |
| Sneider, Jennifer T; Pope Jr, Harrison G; Silveri, Marisa M et al. (2006) Altered regional blood volume in chronic cannabis smokers. Exp Clin Psychopharmacol 14:422-8 |
| Bogorodzki, Piotr; Rogowska, Jadwiga; Yurgelun-Todd, Deborah A (2005) Structural group classification technique based on regional fMRI BOLD responses. IEEE Trans Med Imaging 24:389-98 |
| Tzilos, Golfo K; Cintron, Christina B; Wood, Jonas B R et al. (2005) Lack of hippocampal volume change in long-term heavy cannabis users. Am J Addict 14:64-72 |
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